Modeling and experiments of capillary flow of non-symmetric magnetic fluids under uniform field

摘要

The present work aims to investigate the flow of a non-symmetric ferrofluid undergoing a uniform magnetic field in axial symmetry through both theoretical and experimental approaches. The magneto viscous effect is investigated for a fully developed laminar flow. The governing equations are made non-dimensional in order to identify the physical non-dimensional numbers such as the Peclet number, the particle volume fraction and the parameter of effective applied magnetic field. A regular perturbation method is used to obtain new asymptotic solutions on the limits of very low and very high Peclet numbers. Additionally, numerical integration of the equations system provides a solution for the entire range of Peclet. The magnetization profiles and more global quantities like wall viscosity and the relative viscosity are determined. The numerical and asymptotic solutions present an excellent agreement in the application range of the asymptotic solution. Finally, the magneto viscous effect in capillary flow is also determined through an experimental investigation, showing a very good agreement with the asymptotic solution corresponding to the limit of a low Peclet number.